FIELD OF THE DISCLOSURE
!0002] The present disclosure relates to detecting moisture in a conduit. More
particularly, the present disclosure describes a respiratory or surgical gases conveying system
which 1s capable of detecting the presence, amount and/or location of one or more of
condensation, humidity and/or bodily fluids.
BACKGROUND
[0003] Respiratory assistance apparatuses and surgical insufflators provide a flow
of gases or a flow of pressurized gases through a conduit system to a patient. For a range of
applications using these and similar devices, it is beneficial to humidify the supplied gases.
These applications include where the gases are inspired and/or where the gas is being supplied
during surgery to a surgery site of a patient. A downside to providing humidified gases through
a conduit is the potential for condensation to form within the conduit. In addition to
condensation, other types of moisture may also be introduced into a conduit from the patient
(for example, in the form of bodily f1uids such as saliva, blood, mucus), an optional heat and
moisture exchanger (HME), an optional nebulizer, and/or the environment (such as via a roomentraining
ventilator, or through a liquid- or vapor-permeable conduit wall, for example).
SUJ\i[TVfARY OF THE DISCLOSURE
[0004] Humidified gases can cool as they pass through a conduit system between
a gases source and the gases delivery destination. This can result in moisture (or liquid) forming
inside the conduit as the gases cool. Moisture can refer to condensate, water, or the presence
of any hquid in the conduit. The formation of moisture is typically undesirable in respiratory
ass1stance apparatuses and surgical msuff1ators. For example, condensation in a conduit can
lead to a condition referred to as "rain out.'' Rain out occurs when mmsture forms and
potentially runs down the walls of the conduit system. The moisture can pool m a low part of
the conduit system or it can run out of the conduit system into the patient's resp1ratory system,
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body, back m to the gases source or into a ventilator return or other dev1ce connected to a
conduit of a respuatory assistance apparatus or surgical insufflator. All of these rain out effects
are undesirable and can cause numerous complications. Similarly, fluids from other sources
(including the patient, other eqmpment and/or the environment) may be undesirable, and/or
should be monitored for other reasons.
!0005] As used herem, the phrase "conduit system" encompasses any conduits
(also referred to herein as tubes), connectors or patient interfaces that convey gases between a
gases source and a patient and/or convey expired gases from the patient to another component
of the respiratory assistance apparatus or surgical insufflator. For example, as discussed in
further detail below, the conduit system can include one or more of inspiratory tube(s),
expiratory tube(s), insufi1ation tube(s), connector(s), Y-piece(s), patient tube(s), and/or patient
interface(s) (including masks, nasal cannulas, nasal pillows, endotracheal tubes, tracheostomy
tubes, surgical cannulas, etc.). Further, moisture, condensate, condensation and liquid are
generally used synonymously in the present disclosure as would be understood by a person of
skill in the art from the contextual usage of those terms herein.
[0006] Respiratory assistance apparatuses and surgical insuff1ators (collectively
referred to herein as gases supply systems) can employ one or more heating wires within the
conduit system or in the \valls of any or all components of the conduit system to provide a heat
source. The one or more heating wires allow the conduit to control the temperature and/or
relative humidity of the gases to a desired value or range as the gases pass through the conduit
system, reducing the potential for condensation. One or more sensor \vires can also be included
within or m the walls of the conduit systern as well. The one or more sensor wires are typtcally
used to convey temperature measurernent information of the humidified gases flowmg through
a conduit and/or patient interface frmn one or more ternperature sensors back to a controller of
the gases supply systern. The gases supply system can use the temperature measurement
information m a feedback control system to adjust the amount of heat provided by the one or
more heating wires or other components of the gases supply system.
[0007] Even with heating wires, condensation and rain out can still occur, and
fluids from other sources may still be introduced. The present disclosure provides for detecting
moisture. Mmsture can be detected by measuring or inferring capacitance, reactance and/or
impedance or a change in capacitance, reactance and/or impedance of two or more spaced
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electncal conductors within the conduit system or embedded m the conduit systern walls.
These electrical conductors can be, for example, one or more conductive w1res, such as the one
or more heating wires and/or the one or more sensor w1res. Alternatively, or additionally,
dedicated conductors may be provided within, or embedded m, the conduit system mcluding
the lumen of the conduit. The capacitance can be an intrinsic/parasitic capacitance. The
measure can use a time response and/or a frequency response of the wire(s). Moisture can also
be detected by measuring a change in resistance as disclosed herein and/or a change to a
wireless signal such as an RF. signal.
[0008] The present disclosure provides a humidifier system useable in a gases
supply system, the humidifier system comprising a humidifier; a conduit comprising a first
electrically conductive element and a second electrically conductive element; and a controller
configured to monitor a signal using one or more of the first electrically conductive element
and the second electrically conductive element to determine a value indicative of moisture in
the conduit based at least in part on the signal. The signal can be indicative of a capacitance
between the first electrically conductive element and the second electrically conductive
element The signal can be indicative of a change in capacitance between the first electrically
conductive element and the second electrically conductive element. The controller can
comprise a signal generator. The controller can comprise one or more hardware and/or
software processors. The first electrically conductive element and the second electrically
conductive element can be separated by a distance configured to allow for a capacitive charge
to be sensed bet\.veen the first electrically conductive element and the second electrically
conductive element. The humidifier system can also comprise a dielectnc material located
between the first electrically conductive element and the second electrically conductive
element. The dielectric material can be vapor or liquid permeable. The vapor penneable
dielectric material can allow evaporation of water to ambwnt air while inhibiting passage of
liquid water and breathing gases to ambient air. The controller can be configured to detemune
the value mdicative of moisture on a comparison of a measurement of the first electrically
conductive element and/or the second electrically conductive element. The value mdicative of
mo1sture can comprise a time constant of a c1rcuit compnsmg the first electrically conductive
element or the second electrically conductive element m senes with the reference resistor. The
signal can be indicative of a time constant or a resonant frequency of a circuit compnsing the
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first electncally conductive element and/or the second electrically conductive element. The
signal can be indicative of a change in a time constant or a change m a resonant frequency of
a circuit compnsmg the first electrically conductive element and/or the second electncally
conductive element. The value mductive of mmsture in the conduit corresponds to an
inductance of the conduit. The value mductive of moisture in the conduit corresponds to a
change in inductance of the conduit. The humidifier system can also compnse a resonant circuit
wherein an mductor is placed in parallel with a capacitor. The resonant circuit can be
electrically connected in parallel with the first electrically conductive element, the second
electrically conductive element, or both the first electrically conductive element and the second
electrically conductive element. The resonant circuit can be tuned to exhibit resonant behavior
when sufficiently excited by the signal. The resonant circuit can be tuned to exhibit resonant
behavior when excited by the signal, wherein the signal has been selected to excite the resonant
circuit. The controller can be configured to apply additional power to the first electrically
conductive element in conjunction 'vvith a normal control power. The humidifier system can
also comprise an AC power supply. The humidifier system can also comprise a DC power
supply. The signal can be indicative of a temperature of the first electrically conductive element
or the second electrically conductive element. The signal can be indicative of a change in
temperature of the first electrically conductive element or the second electrically conductive
element The signal can be indicative of a thermal conductivity of a medium between the first
electrically conductive element and the second electrically conductive element, or the signal
can be indicative of a thermal conductivity of a medium proximal to the first electrically
conductive element or the second electncally conductive elernent The signal can be indicative
of a change m thermal conductivity of a medium between the first electrically conductive
element and the second electrically conductive element, or the signal can be indicative of a
change m thermal conductivity of a mediurn proximal to the first electrically conductive
element or the second electncally conductive element. A change m temperature of the first
electrically conductive element or the second electncally conductive elernent can be
substantially linear. The signal can be indicative of a temperature difference between the first
electrically conductive element and the second electrically conductive element. The second
electncally conductive element can measure the s1gnal. The signal can correspond to a
resista.nce of the second electrically conductive element, the res1stance of the second
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electncally conductive elernent varymg with the temperature of the second electncally
conductive element. The first electncally conductive element or the second electrically
conductive element can further comprise a thermistor. The first electrically conductive element
or the second electncally conductive element can further comprise a diode. The diode can be
electncally connected in parallel with the thermistor. The diode can be electrically connected
in parallel, and positioned substantially adjacent, with the thermistor. The first electrically
conductive element and the second electrically conductive element can be adjacent to each
other. The first electrically conductive element and the second electrically conductive element
can be not adjacent to each other. The first electrically conductive element and the second
electrically conductive element can be within a bead of the conduit. The first electrically
conductive element can measure the signal. The signal can be indicative of a resistance of the
first electrically conductive element or the second electrically conductive element. The signal
can be indicative of a resistance of a medium between the first electrically conductive element
and the second electrically conductive element. The first electrically conductive element or the
second electrically conductive element can comprise at least two portions that are electrically
disconnected from one another. The first electrically conductive element and the second
electrically conductive element can be electrically insulated from other electrically conductive
elements for a portion of a length of the first electrically conductive element and for a portion
of a length of the second electrically conductive element. The at least two portions can protrude
into a lumen of the conduit. The at least t\.vo portions can be flush with an inner \vall of the
conduit. The at least two portions can be arranged w-ithin the tube wall and are pneumatically
coupled with the lumen of the conduit. The at least two portions that can be electncally
disconnected from one another can be m series with one another. The at least two portions that
can be electrically disconnected from one another can be m parallel with one another. The
controller can determine a value indicative of moisture in the conduit based at least in part on
a magnitude and/or phase of the s1gnal. The humidifier system can also compnse a signal
generator. The signal can have a frequency between 30Hz and 300 GHz. The s1gnal can have
a frequency between 1 MHz and 100 l'Vlilz. The signal can have a frequency of about 10 MHz.
The first electrically conductive element and/or the second electncally conductive element can
be a quarter of the wavelength of the signal. The wavelength of the signal can be four times
larger than the length of the first electrically conductive element and/or the second electrically
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conductive element. The signal generator can inJect the signal into the first electncally
conductive element. The first electrically conductive element can be configured to be a
transmitter. The second electrically conductive element can be configured to be a receiver to
receive the signal transmitted by the first electrically conductive element. The magnitude
and/or phase of the signal can be measured by a radio-frequency transducer. The radiofrequency
transducer can be an AM receiver, RF sampling ADC, or RF rectifier. The
humidifier system can also comprise a filter to filter the s1gnaL The filter can comprise a high
pass or bandpass filter. The filter can be configured to filter out the mains frequency. The filter
can be configured to filter out frequencies between 50 - 60 Hz. The transmitter can comprise
a loop antenna. The receiver can comprise a loop antenna. The receiver can comprise a
monopole antenna. The transmitter can comprise a monopole antenna. The first electrically
conductive element can be electrically coupled to a first switch. The second electrically
conductive element can be electrically coupled to a second switch. The first switch can be
configured to electrically disconnect one end of the first electrically conductive element. The
second switch can be configured to electrically disconnect one end of the second electrically
conductive element. The first switch and/or the second switch can be located in any one of the
following: a heater base, a sensor cartridge, the conduit, an external component, or an
intermediate connector.
[0009] The controller can be configured to output an alarm if the value indicative
of moisture falls below a first threshold value. The controller can be configured to output an
alarm if the value indicative of condensation exceeds a second threshold value. The alarm
indicates an unacceptable level of rnoisture. The controller can be configured to autornatically
reduce hurnidifi.cation of breathing or insufflation gases in response to the value indicative of
moisture and/or humidity in the conduit The reduction of humidity delivered to the patient can
be achieved by a reduction m heater plate power. The conduit can be a composite conduit. The
conduit can comprise a vapor and/or liquid permeable bead. The permeable bead can allow
evaporation of water to ambient air while inhibiting passage of liquid water and breathmg gases
to ambient air. The permeable bead can be one or more of an activated perfluonnated polymer
matenal havmg extreme hydrophilic properties, hydrophilic thermoplastic, breathable
thermoplastic copolyester, woven treated fabric exhibiting breathable characteristics, or a
hydrophilic polyester block copolymer. The first conductive element and the second
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electncally conductive element can be spirally wound about at least a length of the conduit.
The first conductive element and the second electncally conductive element can be spirally
wound within, through or around the conduit. The first conductive element and the second
electrically conductive element can form part of the conduit walls. The first electrically
conductive element can be a sensmg w1re. The first electncally conductive element can be a
heater wire. The second electrically conductive element can be a sensing wire. The second
electncally conductive element can be a heater wire.
!0010] The present disclosure provides a method of detecting an indication of
moisture in a conduit of a gases supply system used to transport respiratory or surgical gases,
the method comprising determining a presence and/or level of moisture based at least in part
on property of the conduit. The determination of the presence or level of moisture can be
inferred from a dielectric property of the conduit. The determination of the property can
comprise applying a signal to a first electrically conductive element in the conduit.
determination of the property can comprise measuring a capacitance bet\.veen the first
electrically conductive element and a second electrically conductive element. The
determination of the property can comprise measuring a capacitance bet\.veen the first
electrically conductive element and a second electrically conductive element based on the
applied signal. The determination of the prope1iy comprises measuring an indication of a time
constant or a resonant frequency of a circuit comprising the first electrically conductive
element. The determination of the property can comprise processing a value indicative of an
inductance. The determination of the property can further comprise measuring an indication of
a res1stance of the first electrically conductive element. The determmation of the property can
further cmnprise measuring an indication of a temperature. The determination of the property
can further comprise measunng an indication of a thennal conductivity. The determmation of
the property can further comprise measuring a magnitude and/or phase of a s1gnal. The conduit
can be the conduit of any of conduit implernentations disclosed herein. The method uses the
humidifier system of any humidifier systern disclosed herein.
[0011] The present disclosure provides a method of detecting moisture in a conduit
utilized to transport humidified gases, the method comprising providing two electrically
conductive elements separated by a dielectric and located within, around or on the conduit and
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measunng a capacitance or change m capacitance to indicate a measure of mmsture or
condensate within the conduit.
[0012] The present disclosure provides a method of detecting moisture in a conduit
utilized to transport humidified gases, the method comprising providing two electrically
conductive elements located within, around or on the conduit and measuring a resistance or a
change m resistance to indicate a measure of moisture or condensate within the conduit. The
method uses the conduit of any of conduit implementations disclosed herein. The method uses
the humidifier system of any humidifier system disclosed herein.
[0013] The present disclosure provides a method of detecting moisture in a conduit
utilized to transport humidified gases, the method comprising providing two electrically
conductive elements located within, around or on the conduit and measuring a time constant,
a resonant frequency, a change in a time constant, or a change in a resonant frequency to
indicate a measure of moisture or condensate within the conduit. The method uses the conduit
of any of conduit implementations disclosed herein. The method uses the humidifier system of
any humidifier system disclosed herein.
[0014] The present disclosure provides a method of detecting moisture in a conduit
utilized to transpoli humidified gases, the method comprising providing two electrically
conductive elements located within, around or on the conduit and measuring a resistance or a
change in resistance to indicate a measure of moisture or condensate within the conduit. The
method uses the conduit of any of conduit implementations disclosed herein. The method uses
the humidifier system of any humidifier system disclosed herein.
[0015] The present disclosure provides a method of detecting moisture in a conduit
utilized to transport humidified gases, the rnethod cornprising providing two electrically
conductive elernents located witlun, around or on the conduit and measuring a temperature or
a change in temperature to mdicate a measure of moisture or condensate within the conduit.
The method uses the conduit of any of conduit unplement=.ttions disclosed herein. The method
uses the humidifier system of any humidifier system disclosed herein.
[0016] The present disclosure provides a method of detecting moisture in a conduit
utilized to transport humidified gases, the method comprising providing two electrically
conductive elements and located within, around or on the conduit and measuring a thermal
conductivity or a change m thermal conductivity to indicate a measure of moisture or
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condensate within the conduit. The method uses the conduit of any of conduit unplernentations
disclosed herem. The method uses the humidifier system of any humidifier system disclosed
herem.
!0017] The present disclosure provides a method of detecting mmsture in a conduit
utilized to transport humidified gases, the method comprising providing two electncally
conductive elements and located within, around or on the conduit and measuring a magnitude
and/or phase of a s1gnal or a change m a magnitude and/or phase of a s1gnal to indicate a
measure of moisture or condensate within the conduit. The method uses the conduit of any of
conduit implementations disclosed herein. The method uses the humidifier system of any
humidifier system disclosed herein.
[0018] The present disclosure provides external accessories. An example of an
external accessory is a cartridge for use with a humidifier in a respiratory or surgical
humidification system. The present disclosure provides a cartridge for use with a humidifier in
a respiratory or surgical humidification system, the cartridge comprising one or more sensors
for sensing a property of a gases flow in a removable humidification chamber of the humidifier;
a first electrical connector configured to make an electrical connection with a corresponding
electrical connector of the humidifier; a second electrical connector configured to make an
electrical connection with a corresponding electrical connector of an inspiratory conduit
removably engageable with the cartridge, wherein the second electrical connector can
comprise at least a first electrical terminal or pad and a second electrical terminal or pad
configured to make an electrical coupling with a first electrically conductive element and a
second electncally conductive element extending along at least a portion of a length of the
inspiratory conduit; and a controller communicatively coupled with the one or more sensors
and the first electrically conductive element and the second electncal connectors. The cartridge
can be removably attachable to the hurnidifier and the controller can be configured to, rn use,
measure a signal mdicative of a capacitance between the first electrically conductive element
and the second electrically conductive element of the removable insp1ratmy conduit.
[0019] The present disclosure provides a cartridge for use with a humidifier m a
respiratory or surgical humidification system, the cartridge comprising one or more sensors for
sensmg a property of a gases flow in a removable humidification chamber of the humidifier; a
first electrical connector configured to make an electrical connection with a corresponding
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electncal connector of the humidifier; a second electncal connector configured to make an
electrical connection with a corresponding electrical connector of an inspiratory conduit
removably engageable with the cartridge, wherein the second electrical connector can
comprise at least a first electncal terminal or pad and a second electrical terminal or pad
configured to make an electrical coupling with a first electrically conductive element and a
second electrically conductive element extending along at least a portion of a length of the
inspiratory conduit; and a controller communicatively coupled with the one or more sensors
and the first electrically conductive element and the second electrical connectors. The cartridge
can be removably attachable to the humidifier and the controller can be configured to, in use,
measure a signal indicative of a time constant or a resonant frequency of a circuit comprising
the first electrically conductive element and the second electrically conductive element of the
removable inspiratory conduit.
[0020] The present disclosure provides a cartridge for use with a humidifier in a
respiratory or surgical humidification system, the cartridge comprising one or more sensors for
sensing a property of a gases t1ow in a removable humidification chamber of the humidifier; a
first electrical connector configured to make an electrical connection 'vvith a corresponding
electrical connector of the humidifier; a second electrical connector configured to make an
electrical connection with a corresponding electrical connector of an inspiratory conduit
removably engageable with the cartridge, wherein the second electrical connector can
comprise at least a first electrical terminal or pad and a second electrical terminal or pad
configured to make an electrical coupling with a first electrically conductive element and a
second electncally conductive element extending along at least a portion of a length of the
inspiratory conduit; and a controller communicatively coupled with the one or more sensors
and the first electrically conductive element and the second electncal connectors. The cartridge
can be removably attachable to the hurnidifier and the controller can be configured to, rn use,
measure a signal indicative of a resistance of the first electrically conductive elernent or the
second electncally conductive element of the removable inspiratory conduit.
[0021] The present disclosure provides a cartridge for use with a humidifier m a
respiratory or surgical humidification system, the cartridge comprising one or more sensors for
sensmg a property of a gases t1ow in a removable humidification chamber of the humidifier; a
first electrical connector configured to make an electrical connection with a corresponding
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electncal connector of the humidifier; a second electncal connector configured to make an
electrical connection with a corresponding electrical connector of an inspiratory conduit
removably engageable with the cartridge, wherein the second electrical connector can
comprise at least a first electncal terminal or pad and a second electrical terminal or pad
configured to make an electrical coupling with a first electrically conductive element and a
second electrically conductive element extending along at least a portion of a length of the
inspiratory conduit; and a controller communicatively coupled with the one or more sensors
and the first electrically conductive element and the second electrical connectors. The cartridge
can be removably attachable to the humidifier and the controller can be configured to, in use,
measure a signal indicative of a temperature of the first electrically conductive element or the
second electrically conductive element of the removable inspiratory conduit.
!0022] The present disclosure provides a cartridge for use with a humidifier in a
respiratory or surgical humidification system, the cartridge comprising one or more sensors for
sensing a property of a gases flow in a removable humidification chamber of the humidifier; a
first electrical connector configured to make an electrical connection with a corresponding
electrical connector of the humidifier; a second electrical connector configured to make an
electrical connection \Vith a corresponding electrical connector of an inspiratory conduit
removably engageable with the cartridge, wherein the second electrical connector can
comprise at least a first electrical terminal or pad and a second electrical terminal or pad
configured to make an electrical coupling with a first electrically conductive element and a
second electrically conductive element extending along at least a portion of a length of the
inspiratory conduit; and a controller communicatively coupled with the one or more sensors
and the first electrically conductive elernent and the second electrical connectors. The cartridge
can be removably attachable to the humidifier and the controller can be configured to, in use,
measure a s1gnal indicative of a thermal conductivity of a medium between the first electrically
conductive element and the second electncally conductive element of the removable
inspiratory conduit. The present disclosure provides a cartridge for use with a humidifier m a
respiratory or surg1cal humidification system, the cartridge compnsmg one or more sensors for
sensing a property of a gases flow m a removable humidification chamber of the humidifier; a
first electncal connector configured to make an electrical connection with a corresponding
electrical connector of the humidifier; a second electrical connector configured to make an
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electncal connection with a corresponding electrical connector of an mspiratory conduit
removably engageable with the cartridge, wherem the second electrical connector can
comprise at least a first electrical termmal or pad and a second electrical terminal or pad
configured to make an electrical coupling with a first electncally conductive element and a
second electncally conductive element extending along at least a portion of a length of the
inspiratory conduit; and a controller communicatively coupled with the one or more sensors
and the first electrically conductive element and the second electncal connectors. The cartridge
can be removably attachable to the humidifier and the controller can be configured to, in use,
measure magnitude and/or phase of a signal or a change in a magnitude and/or phase of a signal
between the first electrically conductive element and the second electrically conductive
element of the removable inspiratory conduit.
!0023] The present disclosure provides a humidifier useable in a gases supply
system, the humidifier comprising a humidification chamber configured to humidify a gases
supply; an inspiratory conduit connector configured to connection with an inspiratory conduit
including a first electrically conductive element and a second electrically conductive element;
a controller configured to monitor a signal using one or more of the first electrically conductive
element and the second electrically conductive element to determine a value indicative of
moisture in the conduit based at least in pmi on the signal. The controller can be further
configured to monitor the signal. The signal can be indicative of a capacitance bet\veen the
first electrically conductive element and the second electrically conductive element. The signal
can be indicative of a change in capacitance betw-een the first electrically conductive element
and the second electrically conductive element. The signal can be mdicative of a time constant
or a resonant frequency of the first electrically conductive element or the second electrically
conductive element. The signal can be mdicative of a temperature of the first electncally
conductive element or the second electrically conductive element. The signal can be mdicative
of a change in temperature ofthe first electrically conductive elernent or the second electncally
conductive element. The signal can be indicative of a thermal conductivity of a medium
between the first electrically conductive element or the second electncally conductive element,
or the signal or the s1gnal is indicative of a thermal conductivity of a medium proximal to the
first electrically conductive element or the second electrically conductive element. The signal
can be indicative of a change in thermal conductivity of a medium between the first electrically
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conductive element or the second electrically conductive element, or the signal or the s1gnal is
indicative of a change in thermal conductivity of a medium proximal to the first electrically
conductive element or the second electncally conductive element. The signal can be indicative
of a temperature difference between the first electncally conductive element and the second
electncally conductive element. The value mdicative of moisture can be a magnitude and/or
phase of a s1gna! or a change in a magnitude and/or phase of a s1gnal. The controller can
comprise a signal generator. The controller can comprise one or more hardware and/or
software processors. The humidifier can further comprise the conduit of any of conduit
implementations disclosed herein.
!0024] The present disclosure provides a conduit used with a respiratmy or surgical
gases supply system, the conduit comprising a first electrically conductive element; a second
electrically conductive element spaced apart from the first electrically conductive element at a
distance configured to allow a capacitive effect to exist between the first electrically conductive
element and the second electrically conductive element such that the capacitive effect changes
in the presence of moisture; and a material separating the first conductive element from the
second electrically conductive element. At least one of the electrically conductive elements
can be one or more of a heater wire or sensor wire. The conduit can further comprise a
controller configured to determine a presence and/or indication of moisture within the conduit
by determining a capacitance or change in capacitance between the first electrically conductive
element and the second electrically conductive element. The controller can be one or more
microprocessors. The controller can use the first electrically conductive element and second
electncally conductive element to determine the presence or the indication of mmstu.re within
the conduit by measunng a capacitive reactance and/or inductance existing between the first
electncally conductive elernent and the second electncally conductive elernent. The first
electrically conductive element and second electrically conductive element can be placed close
enough to allow for a measurable capacitance, but far enough apart to allow for a measurable
change in capacitance due to a presence of moisture.
[0025] The present disclosure provides a conduit used with a respiratory or surgical
gases supply system, the conduit comprising a first electrically conductive element: a second
electncally conductive element, wherein one or more of the first electrically conductive
element and the second electrically conductive element are configured to provide a
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measurement of a time constant or a resonant frequency mdicative of a presence or amount of
mmsture in a conduit. The conduit can further compnse a resonant circuit wherein an inductive
element is electrically connected in parallel with a capacitive element. One or more of the first
electrically conductive element and the second electrically conductive element can be
configured to be electrically connected in parallel with a resonant circuit wherein an inductive
element is electrically connected in parallel with a capacitive element. The resonant circuit can
be external to the conduit. The resonant circuit can be tuned to exhibit resonant behavior when
excited by a signal. One or more of the first electrically conductive element and the second
electrically conductive element can be configured to be electrically connected in parallel with
a signal generator. The conduit can comprise a controller configured to determine a presence
and/or indication of moisture within the conduit by determining a time constant, a resonant
frequency, a change in time constant, or a change in resonant frequency. One or more of the
first electrically conductive element and the second electrically conductive element can be
configured to be electrically connected in parallel with the controller. The controller can
comprise a signal generator. The controller can be one or more microprocessors.
[0026] The present disclosure provides a conduit used with a respiratory or surgical
gases supply system, the conduit comprising a first electrically conductive element; a second
electrically conductive element, wherein one or more of the first electrically conductive
element and the second electrically conductive element are configured to provide a
measurement of a resistive property indicative of a presence or amount of moisture in a conduit.
The first electrically conductive element or the second electrically conductive element can
comprise at least two portions that are electrically disconnected frmn one another. The at least
two portions can protrude into a lumen of the conduit. The at least two portions can be flush
with an mner wall of the conduit. The at least two portions can be arranged witlun the tube
wall and can be pneumatically coupled with the lumen of the conduit. The at least two portions
that can be electrically disconnected from one another can be in senes with one another. The
at least two portions that can be electrically disconnected frmn one another can be in parallel
with one another. The conduit can further comprise a controller configured to determme a
presence and/or indication of moisture withm the conduit by determming a resistance or change
in res1stance. The controller can be one or more microprocessors.
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[0027] The present disclosure provides a conduit used with a respiratory or surgical
gases supply system, the conduit comprising a first electrically conductive element: a second
electncally conductive element, wherein one or more of the first electrically conductive
element and the second electrically conductive element are configured to provide a
measurement of a temperature or thermal conductivity property indicative of a presence or
amount of moisture in a conduit. The first electncally conductive element or the second
electncally conductive element can further comprise a thermistor. The first electncally
conductive element or the second electrically conductive element can further comprise a diode.
The diode can be electrically connected in parallel with the thermistor. The diode can be
electrically connected in parallel, and positioned substantially adjacent, with the thermistor.
The first electrically conductive element and the second electrically conductive element can
be adjacent to each other. The first electrically conductive element and the second electrically
conductive element can be not adjacent to each other. The first electrically conductive element
and the second electrically conductive element can be within a bead of the conduit. The conduit
can further comprise a controller configured to determine a presence and/or indication of
moisture within the conduit by determining a temperature, a thermal conductivity, a change in
temperature, or a change in thermal conductivity of the first electrically conductive element or
the second electrically conductive element The controller can be configured to apply
additional power to the first electrically conductive element in conjunction with a normal
control power. The controller can be one or more microprocessors.
[0028] The present disclosure provides a conduit used with a respiratory or surgical
gases supply system, the conduit compnsing a first electncally conductive element; a second
electrically conductive element, wherem one or more of the first electncally conductive
element and the second electrically conductive element are configured to measure a magnitude
and/or phase of a signal or a change in a magnitude and/or phase of a signal indicative of a
presence or arnount of rnoisture m a conduit. The first electrically conductive element can be
configured to be a transmitter. The second electrically conductive element can be configured
to be a rece1ver to receive a signal transmitted by the first electrically conductive element. The
transmitter can comprise a loop antenna. The receiver can comprise a loop antenna. The
transmitter can comprise a monopole antenna. The receiver can comprise a monopole antenna.
The first electrically conductive element can be electrically coupled to a first switch. The
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second electrically conductive element can be electrically coupled to a second switch. The first
switch can be configured to electrically disconnect one end of the first electrically conductive
element and the second switch can be configured to electrically disconnect one end of the
second electncally conductive element. The conduit can further comprise a controller
configured to determine a presence and/or mdication of mmsture within the conduit by
determming a magnitude and/or phase of a signal or a change in a magnitude and/or phase of
a signal in the first electncally conductive element or the second electrically conductive
element. The controller can be one or more microprocessors.
[0029] The material can be a fluid permeable material. The first electrically
conductive element and second electrically conductive element can be elongate filaments. The
elongate filament can be surrounded by an electrically insulating jacket. The first electrically
conductive element and second electrically conductive element can be spirally wound about at
least a portion of a length of the conduit. The first electrically conductive element and second
electrically conductive element extend from one end of the conduit to the other end of the
conduit. The first electrically conductive element and second electrically conductive element
extend only a portion of a length from one end of the conduit to the other end of the conduit.
The conduit can include and/or communicate with a controller configured to determine a
presence and/or indication of moisture within the conduit by determining a capacitance or
change in capacitance between the first electrically conductive element and the second
electrically conductive element. The conduit can be a composite conduit. The first electrically
conductive element and second electrically conductive element form part of a wall of the
conduit. The first electrically conductive element and second electrically conductive element
can form part of a bead disposed in a composite conduit. Alternatively, the first conductive
element and second electrically conductive element can be disposed in the conduit such that
the first conductive element and second electrically conductive element can freely move within
the conduit The material can be a vapor and/or liquid permeable material. The matenal can
allow evaporation of water to ambient air while mhibiting passage of liquid water and
breathing gases to ambient air. The material can be a one or more of an activated perfluorinated
polymer material having extreme hydrophilic properties, hydrophilic thermoplastic, breathable
thermoplastic copolyester, woven treated fabric exhibiting breathable characteristics, or a
hydrophilic polyester block copolymer. The conduit can further comprise nucrostructures
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configured to use capillary action to move moisture. The vapor and/or liquid penneable
matenal can be a dielectric matenal. The conduit further can comprise nucrostructures
configured to wick moisture across a portion of the first electrically conductive element and/or
the second electrically conductive element. The conduit further can compnse openings
configured to convey moisture by capillary action between the first electncally conductive
element and the second electrically conductive element. The conduit further can comprise a
w1cking material configured to convey moisture between the first electrically conductive
element and the second electrically conductive element. The first electrically conductive
element and the second electrically conductive element can be ribbon wires. The first
electrically conductive element and the second electrically conductive element can be
comprised within a permeable, non-permeable or partially permeable and non-permeable bead.
The first electrically conductive element and the second electrically conductive element and
bead can be coextruded. The conduit can further comprise an electrically conductive mesh. A
spacing between the first electrically conductive element and the second electrically
conductive element can be variable depending a presence and/or amount of moisture present
within the conduit. The material can cause the first electrically conductive element and the
second electrically conductive element to touch or separate based on a presence of moisture.
The material can comprise an opening, keyhole, dip, channel and/or void configured to allow
moisture between the first electrically conductive element and the second electrically
conductive element and affect a capacitive effect between the first electrically conductive
element and the second electrically conductive element. The first electrically conductive
element and the second electrically conductive elernent can be sensitive to touching of the
conduit The rnaterial can comprise an accordion shape that expands or contracts m the
presence of moisture, thereby movmg the first electrically conductive element and the second
electrically conductive element further apart or closer together. The material can cause the first
electncally conductive element and the second electncally conductive element to touch or
separate based on a presence of moisture.
[0030] The present disclosure provides a humidifier system useable in a gases
supply system, the humidifier system comprising: a humidifier: a conduit comprising a
conductive element; and a controller configured to monitor a signal using the electncally
conductive element to deternune a value indicative of moisture in the conduit based at least in
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part on the signal. The signal can be mdicative of a time constant or a resonant frequency of
the electrically conductive element. The signal can be mdicative of a change in a time constant
or a change m a resonant frequency of the electncally conductive element. The value can be
indicative of moisture m the conduit corresponds to an inductance of the conduit. The value
indicative of moisture in the conduit can correspond to a change in inductance of the conduit.
The humidifier system can further comprise a resonant circuit wherein an inductive element 1s
electncally connected m parallel with a capacitive element. The resonant circuit can be
electrically connected in parallel with the electrically conductive element. The humidifier
system can further comprise a signal generator. The controller can comprise a signal generator.
The controller can comprise one or more hardware and/or software processors. The resonant
circuit can be tuned to exhibit resonant behavior when sufficiently excited by the signal. The
resonant circuit can be tuned to exhibit resonant behavior when excited by the signal, wherein
the signal has been selected to excite the resonant circuit. The controller can be configured to
apply additional po'vver to the electrically conductive element in conjunction with a normal
control power. The humidifier system can further comprise an AC power supply. The
humidifier system can further comprise a DC power supply. The signal can be indicative of a
temperature of the electrically conductive element The signal can be indicative of a change
temperature of the electrically conductive element. The signal can be indicative of a thermal
conductivity of a medium proximal to the electrically conductive element The signal can be
indicative of a change in thermal conductivity of a medium proximal to the electrically
conductive element A change in temperature of the electrically conductive element can be
substantially linear. The electrically conductive element can further comprise a thermistor. The
electrically conductive element can further comprise a diode. The diode can be electrically
connected m parallel with the thermistor. The diode can be electrically connected in parallel,
and positioned substantially adjacent, with the thennistor. The electrically conductive element
can be within a bead of the conduit The electncally conductive element can measure the signal.
The controller can be configured to output an alarm if the value indicative of mmsture falls
below a first threshold value. The controller can be configured to output an alarm if the value
indicative of mmsture exceeds a second threshold value. The alarm indicates an unacceptable
level of mmsture. The alarm indicates an unaccepta.ble level of moisture. The controller can be
configured to automatically reduce humidification of breathmg or insufi1ation gases in
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response to the value mdicative of moisture and/or humidity in the conduit The reduction of
humidity delivered to the conduit can be achieved by a reduction m heater plate power. The
conduit can be a composite conduit. The conduit can comprise a vapor and/or liquid permeable
bead. The permeable bead can allow evaporation of water to ambient air while inhibiting
passage of liquid water and breathmg gases to ambient air. The permeable bead can be one or
more of an activated perfluorinated polymer material having extreme hydrophilic properties,
hydrophilic thermoplastic, breathable thermoplastic copolyester, woven treated fabnc
exhibiting breathable characteristics, or a hydrophilic polyester block copolymer. The
electrically conductive element can be spirally wound about at least a length of the conduit.
The electrically conductive element can be spirally wound within, through or around the
conduit. The electrically conductive element can form part of the conduit walls. The
electrically conductive element can be a sensing wire. The electrically conductive element can
be a heater wire.
[0031] The present disclosure provides a method of detecting moisture in a conduit
utilized to transport humidified gases, the method comprising providing an electrically
conductive elements located within, around or on the conduit and measuring a time constant,
a resonant frequency, a change in a time constant, or a change in a resonant frequency to
indicate a measure of moisture or condensate within the conduit. The method uses the conduit
of any of conduit implementations disclosed herein. The method uses the humidifier system of
any humidifier system disclosed herein.
[OfH2] The present disclosure provides a method of detecting moisture in a conduit
utilized to transport humidified gases, the method comprising providing an electncally
conductive elements located within, around or on the conduit and measuring a temperature or
a change in temperature to indicate a measure of moisture or condensate within the conduit.
The method uses the conduit of any of conduit implementations disclosed herem. The method
uses the humidifier systern of any humidifier system disclosed herem.
[0033] The present disclosure provides a method of detecting mmsture in a conduit
utilized to transport humidified gases, the method comprising providing an electncally
conductive elements and located withm, around or on the conduit and measuring a thermal
conductivity or a change in thermal conductivity to indicate a measure of moisture or
condensate within the conduit. The method uses the conduit of any of conduit implementations
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disclosed herein. The method uses the humidifier system of any humidifier system disclosed
herein.
[0034] The present disclosure provides a cartridge for use with a humidifier m a
respiratory or surgical humidification system, the cartridge comprising one or more sensors for
sensmg a property of a gases flow in a removable humidification chamber of the humidifier; a
first electrical connector configured to make an electrical connection with a corresponding
electncal connector of the humidifier; a second electncal connector configured to make an
electrical connection with a corresponding electrical connector of an inspiratory conduit
removably engageable with the cartridge, wherein the second electrical connector can
comprise at least one electrical terminal or pad configured to make an electrical coupling with
an electrically conductive element extending along at least a portion of a length of the
inspiratory conduit; and a controller communicatively coupled with the one or more sensors
and the first and the second electrical connectors. The cartridge can be removably attachable
to the humidifier, and the controller can be configured to, in use, measure a signal indicative
of a time constant or a resonant frequency of a circuit comprising the electrically conductive
element of the removable inspiratory conduit
[OfH5] The present disclosure provides a cartridge for use with a humidifier in a
respiratory or surgical humidification system, the cartridge comprising one or more sensors for
sensing a property of a gases f1ow in a removable humidification chamber of the humidifier; a
first electrical connector configured to make an electrical connection 'vvith a corresponding
electrical connector of the humidifier; a second electrical connector configured to make an
electncal connection with a corresponding electrical connector of an mspiratory conduit
removably engageable with the cartridge, wherem the second electrical connector can
comprise at least one electrical ternunal or pad configured to make an electrical coupling with
an electrically conductive element extending along at least a portion of a length of the
inspiratory conduit; and a controller communicatively coupled with the one or more sensors
and the first and the second electrical connectors. The cartridge can be removably attachable
to the humidifier, and the controller can be configured to, m use, measure a signal indicative
of a temperature of the electrically conductive element of the removable mspiratory conduit.
[0036] The present disclosure provides a cartridge for use with a humidifier m a
respiratory or surgical humidification system, the cartridge comprising one or more sensors for
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sensmg a property of a gases flow in a removable humidification chamber of the humidifier; a
first electrical connector configured to make an electrical connection with a corresponding
electncal connector of the humidifier; a second electncal connector configured to make an
electrical connection with a corresponding electrical connector of an inspiratory conduit
removably engageable with the cartridge, wherein the second electrical connector can
comprise at least one electncal terminal or pad configured to make an electrical coupling with
an electrically conductive element extending along at least a portion of a length of the
inspiratory conduit; and a controller communicatively coupled with the one or more sensors
and the first and the second electrical connectors. The cartridge can be removably attachable
to the humidifier, and the controller can be configured to, in use, measure a signal indicative
of a thermal conductivity of a medium proximal to the electrically conductive element of the
removable inspiratory conduit.
[0037] The present disclosure provides a humidifier useable in a gases supply
system, the humidifier comprising a humidification chamber configured to humidify a gases
supply; an inspiratory conduit connector configured to connection with an inspiratory conduit
including an electrically conductive element; a controller configured to monitor a signal using
the electrically conductive element to determine a value indicative of moisture in the conduit
based at least in pmi on the signal. The signal can be indicative of a time constant or a resonant
frequency of the electrically conductive element. The signal can be indicative of a temperature
of the electrically conductive element. The signal can be indicative thermal conductivity of a
medium proximal to the electrically conductive element The controller can comprise a signal
generator. The controller can compnse one or rnore hardware and/or software processors. The
humidifier can further comprise the conduit of any of conduit implementations disclosed
herem.
[0038] The present disclosure provides a conduit used with a respmlt.ory or surgical
gases supply system, the conduit comprising an electrically conductive element, wherein the
electrically conductive element is configured to provide a measurement of a time constant or
a resonant frequency indicative of a presence or amount of moisture in a conduit. The conduit
can further comprise a resonant circuit wherein an inductive element 1s electrically connected
in parallel with a capacitive element The resonant circuit can be external to the conduit. The
resonant circuit can be tuned to exhibit resonant behavior when sufficiently excited by the
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s1gnal The resonant c1rcuit can be tuned to exhibit resonant behavior when excited by the
signal, wherein the signal has been selected to excite the resonant circuit. The electrically
conductive element can be configured to be electrically connected in parallel with a signal
generator. The conduit can further comprise a controller configured to determine a presence
and/or indication of moisture within the conduit by determinmg a time constant, a resonant
frequency, a change in time constant, or a change in resonant frequency. The electrically
conductive can be configured to be electrically connected in parallel with the controller. The
controller can comprise a signal generator. The controller can comprise one or more
m1croprocessors.
!0039] The present disclosure provides a conduit used with a respiratmy or surgical
gases supply system, the conduit comprising an electrically conductive element, wherein the
electrically conductive element is configured to provide a measurement of an temperature or
thermal conductivity property indicative of a presence or amount of moisture in a conduit. The
electrically conductive element can further comprise a thermistor. The electrically conductive
element can further comprise a diode. The diode can be electrically connected in parallel with
the thermistor. The diode can be electrically connected in parallel, and positioned substantially
adjacent, with the thermistor. The electrically conductive element can be within a bead of the
conduit. The conduit can fmiher comprise a controller configured to determine a presence
and/or indication of moisture 'vvithin the conduit by determining a temperature and/or a change
in temperature of the electrically conductive element, and/or by determining a thermal
conductivity of a medium proximal to the electrically conductive element and/or a change in
thermal conductivity of a medium proximal to the electncally conductive element. The
controller can be configured to apply additional power to the electncally conductive element
in conjunction with a normal control power. The controller can be one or rnore microprocessors
[0040] The present disclosure can be applied to any known conduit with two
electncally conductive elements. The material can be a fluid permeable matenal. The
electrically conductive element can be elongate filaments. The elongate filament can be
surrounded by an electncally msulating jacket. The electrically conductive element can be
spirally wound about at least a portion of a length of the conduit. The electrically conductive
element extend from one end of the conduit to the other end of the conduit. The electncally
conductive element extend only a portion of a length from one end of the conduit to the other
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end of the conduit. The conduit can be a composite conduit. The electrically conductive
element can form part of a wall of the conduit. The electrically conductive element can form
part of a bead disposed in a composite conduit. Alternatively, the first conductive element and
second electrically conductive element can be disposed in the conduit such that the first
conductive element and second electrically conductive element can freely move within the
conduit. The matenal can be a vapor and/or liquid permeable material. The matenal can allow
evaporation of water to ambient air while inhibiting passage of liquid water and breathing gases
to ambient air. The material can be a one or more of an activated perfluorinated polymer
material having extreme hydrophilic properties, hydrophilic thermoplastic, breathable
thermoplastic copolyester, woven treated fabric exhibiting breathable characteristics, or a
hydrophilic polyester block copolymer. The conduit can further comprise microstructures
configured to use capillary action to move moisture. The vapor and/or liquid permeable
material can be a dielectric material. The conduit further can comprise microstructures
configured to wick moisture across a portion of the electrically conductive element. The
conduit further can comprise openings configured to convey moisture by capillary action. The
conduit further can comprise a wicking material configured to convey moisture. The
electrically conductive element can be ribbon wires. The electrically conductive element can
be comprised within a permeable, non-permeable or partially permeable and non-permeable
bead. The electrically conductive element and bead can be coextruded. The conduit can further
comprise an electrically conductive mesh. The electrically conductive element can be sensitive
to touching of the conduit.
[0041] Although discussed mamly with respect to respiratory assistance
apparatuses and surg1cal insufflators, it is to be understood that the moisture detection
disclosure provided by the present apphcation can also apply to other medical or non-medical
uses of a conduit or humidified gases transport system where it is desirable to detect a presence
or extent of mmsture.
BRIEF DESCRIPTION OF THE DRAWINGS
!0042] These and other features, aspects, and advantages of the present disclosure
are described with reference to the drawings of certam unplementations, wh1ch are intended to
schematically illustrate certain implementations and not to limit the disclosure.
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[0043] Fig lA illustrates schernatically an example respiratory humidifier system.
!0044] Fig. 1B illustrates an example humidifier.
[0045] Fig. 1 C illustrates an example heater base and cartridge.
!0046] Fig. lD illustrates an example humidifier with the electropneumatic
connector disconnected from the humidifier of FIG. lB.
lB.
!0047] Fig, 1E illustrates an example heater base and humidification chamber.
[0048]
!0049]
Fig. IF illustrates an example cartridge.
Fig. 1 G illustrates the electropneumatic connector of the humidifier of Fig.
!0050]
[0051]
conduit.
[0052]
Fig. 2 illustrates schematically an example surgical humidifier system.
Fig. 3A shows a side-plan view of a section of an example composite
Fig. 3B shows a longitudinal cross-section of a top portion a tube similar to
the example composite conduit of Fig. 3A.
[0053] Fig. 3C shows another longitudinal cross-section illustrating a first elongate
member in the composite conduit.
[0054] Fig. 4A illustrates condensation interaction with a non-permeable bead of a
composite conduit
[0055] Fig. 4B illustrates condensation interaction with a permeable bead of a
composite conduit
[0056] Fig. 5 illustrates an example modeled circuit system of a condensation
detection system using capacitance to detect condensation.
[0057] Fig. 6 illustrates an example modeled circuit system of a condensation
detection system using a time constant or resonance frequency derived from inductance to
detect condensation.
[0058] Fig 7 illustrates an example modeled circuit systern of a condensation
detection system using res1stance to detect condensation.
[0059] Fig. 8 illustrates an example modeled circuit system of a condensation
detection system using res1stance and short-circuiting to detect condensation.
[0060] Fig. 9A illustrates schematically an example condensation detection system
using signal attenuation to detect condensation.
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[0061] Fig 9B illustrates a conduit wall structures configured to detect mmsture
using signal attenuation.
[0062] Fig. 1 OA illustrates an example modeled circuit system of a condensation
detection system using signal attenuation to detect condensation.
[0063] Fig. 1 OB illustrates an example modeled circuit system of a condensation
detection system using signal attenuation to detect condensation with monopoles.
[0064] Fig. llA illustrates heat radiating from w1res in a bead.
!0065] Fig. liB illustrates an example modeled circuit system of a condensation
detection system using temperature or thermal conductivity to detect condensation.
!0066] Fig. 12 illustrates a table of resistor voltage vs. time constant m a
condensation detection system.
[0067] Fig. 13A illustrates a flow chart of a condensation detection mode.
[0068] Fig. l3B illustrates a flow chart of a condensation measurement mode.
[0069] Fig 13C illustrates a f1ow chart of a condensation measurement mode using
resonant frequency.
[0070] Fig 13D illustrates a flow chart of a condensation measurement mode using
signal attenuation.
[0071] Fig 13E illustrates a f1ow chart of a condensation measurement mode using
thermal conductivity.
[0072] Fig 14 illustrates an example bead. vanous conduit wall structures
configured to detect moisture.
[0073]
[0074]
open mg.
[0075]
tube wall.
[0076]
of the tube wall.
!0077]
[0078]
!0079]
Fig 15 illustrates an example configuration of a bead with an opening.
Fig. 16 illustrates a second example configuration of a bead with an
Fig. 17 A illustrates an example configuration cross section of a part of the
Fig. 17B illustrates a second example configuration cross section of a part
Fig. 18 illustrates a portion of the tube wall with parallel elements.
Fig. 19 illustrates a portion of the tube wall where the elements can pivot.
Fig. 20 illustrates an example of a permeable wall portion of a conduit wall.
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[0080] Fig 21 illustrates a second example of a permeable wall portion of a conduit
walL
[0081] Fig. 22 illustrates an example conduit configuration where elements are in
the same plane, parallel to the surface of the exterior conduit walL
[0082] Fig. 23 illustrates a cross section of an example conduit wherein the
elements are provided longitudinally, parallel to the lumen, and equidistantly spaced about the
circumference of the tube
!0083] Fig. 24 illustrates a cross section of an example conduit wherein an
additional conductive element wound about the outside of the conduit wall.
[0084] Fig. 25 illustrates a cross section of an example conduit wherein individual
strands of two meshes can be insulated and multiplexed.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0085] Although ce1iain implementations and examples are described below, those
of skill in the art will appreciate that the disclosure extends beyond the specifically disclosed
implementations and/or uses and obvious modifications and equivalents thereof Thus, it is
intended that the scope of the disclosure herein disclosed should not be limited by any
particular implementations described below. For example, the dimensions provided in the
present disclosure are examples and not being limiting. Similarly, although described mainly
with respect to respiratory or surgical humidification systems, the present disclosure is
applicable to any tubing arrangement where it is desirable to measure moisture. The folknving
examples describe detection of a presence and, optionally, volume and/or location of
condensation in particular (for example, condensed water or other humidifying liquids), but
the disclosed methods and apparatuses may alternatively or additionally be applied to detect
humidity of the gases and/or the presence of other moisture or fluids within the conduit system.
Example Gases Supplv Svstems
[0086] Fig, 1 schematically illustrates an example respuatory assistance apparatus
including a conduit system comprising one or more conduits 103, 117, a patient interface 115
and a Y-piece 135. The respiratory assistance apparatus may be a ventilator, a continuous,
variable, or bi-level positive airway pressure (PA.P) system or other form of respiratory
therapy, such as, for example, high i1ow therapy.
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[0087] Gases may be transported m the breathing circuit of Fig, 1 as follows. Dry
or relatively dry gases pass from a gases source l 05 through a dry line tube 1 57 to a humidifier
107, which humidifies the dry gases. The gases source 105 may be, for example, a ventilator
or a blower. The humidifier 107 connects to an end l 09 of a conduit, such as inspiratory tube
103, via a port 111. The inspiratory tube 103 is connected to a patient 101 through a patient
interface 115, optionally using a Y -piece 113. An optional expiratory conduit, such as
expiratory tube 117, also connects to the patient interface 115 through the Y-pwce 113. The
expiratory tube may be configured to move exhaled gases away from the patient 101. As
illustrated in Fig. l, expiratory tube 117 returns exhaled gases from the patient 101 to the gases
source 105. Alternatively, the inspiratory tube 103 connects directly to the patient interface
115 without a '{-piece 113. In such an implementation, expired gases are allowed to flow
directly to the ambient environment.
[0088] Inspiratory tube l 03 can include electrically conductive elements such as
heater, sensor and/or moisture detection elements 145. Similarly, expiratory tube 117 can
include heater, sensor and/or moisture detection elements 147. Further, theY-piece 113 and
patient interfac.e 115 can also include heater, sensor and/or moisture detection elements. As
will be explained in further detail below, the heater, sensor and/or moisture detection elements
145, 147 can be wires or filaments.
[0089] As shown in the example respiratory assistance apparatus of Fig, 1, dry or
relatively dry gases enter the gases source 1 05 through a vent 119. A fan 121 may improve gas
f1ow into the gases source 105 by drawing air or other gases through the vent 119. The fan 121
may be, for instance, a variable speed fan, where an electronic controller 123 controls the fan
speed. The electromc controller 123 may also be controlled by a second electronic controller
125, or vice versa, in some implementations.
[0090] The humidifier 107 can include a hurnidification chamber 129 containmg a
volume of water 130 or other suitable humidifying hquid. The humidification chamber 129
can be rernovable frmn the humidifier 1 07. The humidification chamber 129 rnay include a
highly heat-conductive base (for example, an aluminum base) contacting or assocmted with a
heater plate 131 on the humidifier l 07.
[0091] The humidifier 107 may also include electronic controls. ln Fig. l, for
example, the humidifier 107 includes an electromc, analog, or digital controller 125. The
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controller 125 may be a rnicroprocessor-based controller executmg computer software
commands stored in associated memory. In response to humidity, temperature or other
feedback values provided v1a a user interface 133 and/or integrated sensors, the controller 125
determmes heat, flow, pressure and/or other variables used to provide humidified gases to a
patient (also referred to herein as a user). User mterface 133 can be one or more hardware
buttons and/or a display or touch screen display. The display can provide audio and/or visual
feedback to the user. When condensation is detected, any number of alarms, alerts, feedback,
guidance or instructions can be provided to the user to indicate the presence, extent or remedies
for a condensation condition. For example, the user interface can provide an alarm when
condensation is detected. The user interface can provide a visual indication of condensation.
The user interface can also provide an animation to instruct a user how to properly drain
condensation.
[0092] Any suitable patient interface may be used. Patient interface is a broad term
and is to be given its ordinary and customary meaning to a person of ordinary skill in the mi
(that is, it is not to be limited to a special or customized meaning) and includes, without
limitation, masks (such as tracheal mask, face masks, and nasal masks), endotracheal tubes,
tracheostomy tubes, cannulas, and nasal pillows. A temperature probe 135 may be incorporated
in or connected to inspiratory tube 103 near theY-piece 113, or directly to theY-piece 113 or
the patient interface 115. The temperature probe 13 5 monitors the temperature of the flo\v of
gases near or at the patient interface 115. A heating vv-ire (such as element 145) may be used to
adjust the temperature of the patient interface 115, theY-piece 113, and/or the inspiratory tube
l 03 to maintain the temperature of the tlow of gases above the saturation temperature, thereby
reducing the opportunity for unwanted condensation, and/or to deliver the gases at optirnal
temperature for patient therapy (for example, 40°C at the patient end of the insp1ratmy tube
and/or 37°C at the patient for non-invasive therapy). As shown in Fig l, exhaled gases are
optionally returned from the patient interface 115 to the gases source l 05 vm the expiratory
tube 117
[0093] The system of Fig. 1 may be readily adapted for other applications involving
the supply of a heated and/or humidified gas flow to a user or patient, including but not limited
to laparoscopy, and the like. Such applications may use alternative gases, operating parameters
(e.g., i1ow, pressure, temperature, or humidity) and patient interfaces. Further, although shown
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with respect to a separate ventilator and humidifier system, it is to be understood that the
present disclosure can also be used with an mtegrated ventilator/blower and humidifier system.
[0094] The system of Fig. 1 can also provide oxygen (Ch) or an 02 fraction to the
user through port 149. The system of Fig. 1 can receive 02 from a remote source and/or by
blending atmospheric air with incoming 02 from the remote source. The blending of
atmospheric air and mcoming 02 can occur via a Venturi or a similar inlet located m gases
source 1 05 or humidifier 107.
!0095] Fig, 1B illustrates in more detail an example respiratory humidifier. Aside
from the differences described below, the humidifier is otherwise similar to the humidifier 107
of the system illustrated in Fig. 1A.
[0096] The illustrated humidifier comprises a heater base 151 with a heater plate,
a user interface and a controller; a removable and replaceable humidification chamber 153;
and a removable and replaceable cartridge 155. The humidification chamber 153 is received
by the heater base 151, in thermal contact with the heater plate 152.
[0097] The cartridge 155 houses electronics and one or more sensors which sense
one or more properties of gases flowing through the humidification chamber in use. The
sensors may be provided on probes protruding from the cartridge and through an aperture in
the in let or outlet of the humidification chamber, in use. The cmiridge also comprises an
electrical connector which makes an electrical connection with the heater base for
communication (for example, serial communication) with the controller. The cartridge may
further house, in part or in whole, electronics configured to determine or infer a capacitance or
change in capacitance of the inspiratory tube, as described in further detail below, and
communicate this to the controller via the electncal connector. The cartridge therefore
preferably compnses a rnicrocontroller commumcatively coupled with the sensor(s) and the
controller. Alternatively, or additionally, the controller provided within the heater base, in part
or in whole, may be configured to determine or infer the capacitance from data received from
the sensor(s) via the electrical connection.
[0098] In use, the outlet of a dry line tube 157 receivmg a flow of gases from a
gases source is pneumatically coupled with the inlet of the humidification chamber 153, and
an mspiratory tube 159 comprising an electropneumatic connector 161 1s electncally coupled
with the cartridge and pneumatically coupled with the outlet of the humidification chamber
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153 to transport the humidified flow of gases towards the patient The electropneurnatic
connector makes a releasable and lockable connection with the humidification chamber and/or
cartridge, and compnses release buttons 163.
!0099] The electropneumatic connector 161, shown m further detail in Fig. 1C,
comprises electncal terminals or pads 171 respectively coupled with a pair of sensor wires 173
and a pair of heater w1res 175 embedded within the inspiratory tube, fornung respective sensing
and heating loops. It also comprises electrical termmals or pads 171 electrically coupled with
an identification resistor or other identification element embedded within the electropneumatic
connector 161, which may be used by the humidifier to identify the type of inspiratory tube
coupled with the cartridge. As described in further detail, moisture within the inspiratory
conduit may be detected from a measure of capacitance between the electrically-isolated
heating and sensing loops. The connector may further comprise additional wires or conductors
configured to detect moisture within the inspiratory tube, alone or in combination with one or
more of the sensor or heater wires. Corresponding moisture detection terminals or pads 171
can also be included. Alternatively, the additional wires or conductors may be electrically
coupled with the 'identification' terminals or pads in place of the identification resistor or other
identification element, and may optionally have a predetermined resistance (or a resistance
within a predetermined range), capacitance, or resonant frequency unique to each tube model.
This arrangement provides the dual functionality of identification and moisture detection. For
example, a moisture-detection 'vvire having a particular resistance may be used by the
humidifier to identify the tube as being configured for capacitive moisture detection, and/or
enable calibration of the cartridge and/or heater base for moisture detection with that particular
tube model.
[0100] The aforementioned electrical tenninals or pads 171 of the
electropneumatic connector 161 are configured to make an electrical connection with
corresponding pads or terminals on the cartridge (155 of Fig, 1 B). Thus, existing humidifier
bases may be retrofitted with a replacement cartridge comprising any additional electronics
and/or electrical pads or terminals reqmred to detect moisture m the inspiratory tube. Similarly,
the disclosed humidifier may be retrofitted with a replacement cartridge for compatibility with
alternative insp1ratory conduits, if necessary. Alternatively, the electrical termmals or pads of
the electropneumatic connector and cartridges may be arranged so that selected "core"
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terminals or pads make electrical connections with corresponding terminals or pads of two or
more different cartridges, while "optional" terminals or pads make electrical connections only
with specific terminals or pads of selected cartridges configured to make use of those
connections.
[0101] At a distal (patient) end of the inspiratory conduit, there is provided a
temperature sensor electrically coupled to the pair of embedded sensing wires, forming the
sensmg loop, and the heating wires are also electrically coupled with each other, forming the
heating loop. The additional wire( s) or conductor( s) may similarly be electrically coupled at
the distal end of the tube, although this may not be required in at least some implementations.
!0102] The cartridge may further comprise a connector and/or cable configured for
connection to a corresponding connector of the expiratory conduit (14 7 of Fig. 1 A) to supply
power to expiratory heating wire(s). In some implementations, the cartridge and expiratory
conduit may alternatively or additionally be configured to detect moisture in the expiratory
tube, with the connector and/or cable providing the required electrical connections.
[0103] Fig, 2 illustrates an example surgical insufflation device that can be used,
for example, in a laparoscopy procedure. The laparoscopic cannula 207 can be connected to a
gases delivery conduit 206, for example, via a Luer lock connector 4. The cannula 207 can be
used to deliver gases into a surgical site, such as 'vvithin the cavity of the patient 2. The cannula
207 can include one or more passages to introduce gases and/or one or more surgical
instruments into the surgical cavity. The surgical instrument can be a scope, electrocautery
tool, or any other instrument The surgical instrument can be coupled to an imaging device,
which can have a screen. The imaging device can be part of a surgical stack, which can include
a plurality of surgical tools and/or apparatuses.
[0104] The hmnidifier chamber 205 can optionally or preferably be in serial
connection to a gases supply 9 via a further conduit 204. The gases supply 9 can provide one
or more insutllation gases, such as carbon dioxide, to the humidifier chamber 205. The gases
supply can provide a continuous gases tlow or an intermittent gases flow. The gases can be
humidified as they are passed through the humidifier chamber 205, wh1ch can contain a volume
of water 220.
[0105] A humidifier that mcorporates the humidifier chamber 205 can be any type
of humidifier. The humidifier chamber 205 can mclude a plastic formed chamber having a
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metal or otherwise conductive base sealed thereto. The base can be in contact with the heater
plate 212 dunng use. The volume of water 220 contained in the chamber 205 can be heated by
a heater plate 212, which can be under the control of a controller or control means 208 of the
humidifier. The volume of water 220 withm the chamber 205 can be heated such that it
evaporates, mixing water vapor with the gases flowmg through the chamber 205 to heat and
humidify the gases.
[0106] The controller or control means 208 can be housed in a humidifier base unit
221, which can also house the heater plate 212. The heater plate 212 can have an electric
heating element therein or in thermal contact therewith. The humidifier base unit 221 and/or
the heater plate 212 can be removably engageable with the humidifier chamber 205. The
humidifier chamber 205 can also alternatively or additionally include an integral heater.
[0107] A temperature sensor can also be located at or near the outlet 209 to monitor
a temperature of the humidified gases leaving the humidifier chamber 205 from the outlet 209.
Additional sensors can also optionally be incorporated, for example, for sensing characteristics
of the gases (such as temperature, humidity, flow, or others) at a patient end or anywhere along
the gases delivery conduit 206. The temperature sensor can be connected to the controller 208
through a sensor wire within, throughout, or around gases delivery conduit 206
[0108] The gases can exit out through the humidifier's outlet 209 and into the gases
delivery conduit 206. The gases can move through the gases delivery conduit 206 into the
surgical cavity of the patient 2 via the cannula 207, thereby inf1ating and maintaining the
pressure within the cavity Preferably, the gases leaving the outlet 209 of the humidifier
chamber 205 can have a relative humidity of around 100%. The gases travel along the gases
delivery conduit 206. As with all of the various example humidifier systems discussed above,
"ram out" can occur such that water vapor can condense on a wall ofthe gases delivery conduit
206. Condensate can have undesmJ.ble effects, such as detnmentally reducing the water content
of the gases delivered to the patient. In order to reduce and/or minirnize the occurrence of
condensation within the gases delivery conduit 206, a heater wire 210 can be provided within,
throughout, or around the gases delivery conduit 206. The heater wire 210 can be electromcally
connected to the humidifier base unit 221, for example by an electrical pneumatic connector
of gases delivery conduit 206.
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Composite Tubes
!0109] Fig. 3A shows a side-plan view of a section of an example composite
conduit or tube 301. ln general, the composite tube 301 comprises a first elongate member 303
and a second elongate member 305. Member is a broad term and is to be given its ordinary and
customary meaning to a person of ordinary skill in the art, is not to be limited to a special or
customized meaning, and includes, without limitation, mtegral portions, mtegral components,
and distinct components. Thus, although Fig. 3A illustrates an implementation made of two
distinct components, it will be appreciated that in other implementations, the first elongate
member 303 and second elongate member 305 can also represent regions in a tube formed
from a single material. Thus, the first elongate member 303 can represent a hollow portion of
a tube, while the second elongate member 305 can represent a structural supporting or
reinforcement portion of the tube which adds structural support to the hollow portion. The
hollow portion and the structural supporting portion can have a spiral configuration, as
described herein. The composite tube 301 may be used to form the inspiratory tube and/or the
expiratory tube of any type of system as described above, a coaxial tube as described below,
or any other tubes as described elsewhere in this disclosure.
[0110] In this example, the first elongate member 303 comprises a hollow body
spirally wound to form, at least in part, an elongate tube having a longitudinal axis I~A-Land a lumen 307 extending along the longitudinal axis I~A-LA. In at least one
implementation, the first elongate member 303 is helical tubular member. Preferably, the first
elongate member 303 is flexible. Furthermore, the first elongate member ~)03 is preferably
transparent or, at least, semi-transparent or serni-opaque. A degree of optical transparency
allows a caregiver or user to inspect the lumen 307 for blockage or contaminants or to confirm
the presence of condensate. A variety of plastics, mcluding medical grade plastics, are suitable
for the body of the first elongate rnember 303. Examples of suitable materials mclude
Polyolefin elastorners, Polyether block amides, Thermoplastic co-polyester elastomers,
EPDM-Polypropylene rnixtures, and Thennoplastic polyurethanes.
[0111] The hollow body structure of the first elongate member 303 contributes to
the insulating properties to the composite tube 301. An msulating tube 30lls desirable because,
as explained above, it prevents heat loss. This can allow the tube 301 to deliver gas from a
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heater-humidifier to a patient while arnehorating heat loss and condensation with nunimal
energy consumptwn.
[0112] The hollow portion of the first elongate member 303 can optionally be filled
with a gas. The gas can be air, which 1s desirable because of its low thermal conductivity
(2.62xl0-2 W/mK at 300K) and very low cost. A gas that 1s more viscous than air may also
advantageously be used, as lugher viscosity reduces convective heat transfer. Thus, gases such
as argon (17.72xl0-3 W/mK at 300K), krypton (9.43x1o-' W/mK at 300K), and xenon
(5.65xl0-3 \V/ mK at 300K) can increase insulating performance. Each of these gases is nontoxic,
chemically inert, fire-inhibiting, and commercially available. The hollow portion of the
first elongated member 303 can be sealed at both ends of the tube, causing the gas within to be
substantially stagnant. Alternatively, the hollow portion can be a secondary pneumatic
connection, such as a pressure sample line for conveying pressure feedback from the patientend
of the tube to a controller. The first elongate member 303 can be optionally perforated. For
instance, the surface of the first elongate member 303 can be perforated on an outward-facing
surface, opposite the lumen 307. The hollow portion of the first elongate member 303 can also
optionally be filled with a liquid. Examples of liquids can include \Vater or other biocompatible
liquids with a high thermal capacity. For instance, nanof1uids can be used. An example
nanof1uid with suitable thermal capacity comprises water and nanoparticles of substances such
as aluminum.

\VHA T lS CLAIMED lS:
l. A humidifier system useable in a gases supply system, the humidifier system
compnsmg:
a humidifier;
a conduit comprising:
a first electrically conductive element; and
a second electncally conductive element;
a controller configured to monitor a signal using one or more of the first electrically
conductive element and the second electrically conductive element to determine a value
indicative of moisture in the conduit based at least in part on the signal.
2. The humidifier system of Claim 1, wherein the signal is indicative of a capacitance
between the first electrically conductive element and the second electrically conductive
element.
3. The humidifier system of Claim 1, wherein the signal is indicative of a change in
capacitance between the first electrically conductive element and the second electrically
conductive element.
4. The humidifier system of any of Claims 1-3, fmiher comprising a signal generator.
5. The humidifier system of any of Claims 1-3, wherein the controller comprises a
signal generator.
6. The humidifier system of any of Claims 1-5, wherein the controller comprises one
or more hardware and/or software processors.
7. The humidifier system of any of Claims 1-6, the first electrically conductive
element and the second electrically conductive element are separated by a distance configured
to allow for a capacitive charge to be sensed between the first electncally conductive element
and the second electrically conductive element.
8. The humidifier system of any of Claims 1-7, further compnsmg a dielectnc material
located between the first electrically conductive element and the second electrically conductive
element.
9. The humidifier system of Claim 8, wherein the dielectric material is vapor or liquid
permeable.
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1 0. The humidifier systern of Clann 9, wherein the vapor permeable dielectric material
allows evaporation of water to ambient mr while mhibiting passage of liquid water and
breathing gases to ambient air.
11. The humidifier system of any of Claims 1-10, wherein the controller 1s configured
to determine the value indicative of moisture based on a comparison of a measurement of the
first electrically conductive element and/or the second electrically conductive element.
12. The humidifier system of Claim 11, wherem the value indicative of mmsture
comprises a time constant of a circuit comprising the first electrically conductive element or
the second electrically conductive element in series with the reference resistor.
13. The humidifier system of Claim 1, wherein the signal is indicative of a time
constant or a resonant frequency of a circuit comprising the first electrically conductive
element and/or the second electrically conductive element.
14. The humidifier system of Claim 1, wherein the signal is indicative of a change in a
time constant or a change in a resonant frequency of a circuit comprising the first electrically
conductive element and/or the second electrically conductive element.
15. The humidifier system of any of Claims 1 or 13-14, wherein the value indicative of
moisture in the conduit corresponds to an inductance of the conduit.
16. The humidifier system of any of Claims 1 or 13-14, wherein the value indicative of
moisture in the conduit corresponds to a change in inductance of the conduit.
17. The humidifier system of any of Claims 1 or 13-16, further comprising a resonant
circuit wherein an inductive element is electrically connected in parallel with a capacitive
element.
18. The humidifier system of Claim 17, wherein the resonant circuit is electrically
connected in parallel the c1rcuit cornprising the first electrically conductive element and/or the
second electncally conductive element
19. The humidifier system of any of Claims 13-18, further compnsmg a signal
generator.
20. The humidifier system of any of Claims 13-18, wherem the controller compnses a
signal generator.
21. The humidifier system of any of Cla1ms 13-20, wherein the controller comprises
one or more hardware and/or software processors.
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22. The humidifier system of any of Claims 17-21, wherein the resonant circuit is tuned
to exhibit resonant behavior when sufficiently excited by the signaL
23. The humidifier system of any of Claims 17-21, wherein the resonant circuit is
tuned to exhibit resonant behavior when excited by the signal, wherein the signal has been
selected to excite the resonant circuit.
24. The humidifier system of Claim 1, wherein the controller is configured to apply
additional power to the first electrically conductive element in conjunction with a normal
control power.
25. The humidifier system of any of Claims 1 or 24, further comprising an AC power
supply.
26. The humidifier system of any of Claims l or 24-25, further comprising a DC power
supply.
2 7. The humidifier system of any of Claims 1 or 24-26, wherein the signal is indicative
of a temperature of the first electrically conductive element or the second electrically
conductive element.
28. The humidifier system of any of Claims 1 or 24-26, wherein the signal is indicative
of a change in temperature of the first electrically conductive element or the second electrically
conductive element.
29. The humidifier system of any of Claims 1 or 24-26, wherein the signal is indicative
of a thermal conductivity of a medium between the first electrically conductive element and
the second electrically conductive element, or the signal is indicative of a thermal conductivity
of a medium proximal to the first electrically conductive element or the second electncally
conductive element.
30. The humidifier systern of any of Claims 1 or 24-26, wherein the signal is indicative
of a change m thermal conductivity of a medium between the first electrically conductive
element and the second electrically conductive element, or the signal is mdicative of a change
in thermal conductivity of a rnedium proxunal to the first electrically conductive element or
the second electrically conductive element.
31. The humidifier system of any of Cla1ms 1 or 24-26, wherein the signal is mdicative
of a temperature difference between the first electrically conductive element and the second
electrically conductive element.
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32. The humidifier systern of any of Claims 1 or 24-31, wherein a change in
temperature of the first electrically conductive element or the second electncally conductive
element is substantially linear.
33. The humidifier system of any of Claims 1 or 24-32, wherein the first electrically
conductive element measures the s1gnal.
34. The humidifier system of any of Claims 1 or 24-32, wherein the second electrically
conductive element measures the s1gnal.
3 5. The humidifier system of any of Claims 1 or 24-34, wherein the signal corresponds
to a resistance of the second electrically conductive element, the resistance of the second
electrically conductive element varying with the temperature of the second electrically
conductive element.
36. The humidifier system of any of Claims 1 or 24-35, wherein the first electrically
conductive element or the second electrically conductive element further comprises a
thermistor.
37. The humidifier system of any of Claims 1 or 24-36, wherein the first electrically
conductive element or the second electrically conductive element further comprises a diode.
38. The humidifier system of Claim 37, wherein the diode is electrically connected in
parallel with the thermistor.
39. The humidifier system of Claim 37, wherein the diode is electrically connected in
parallel, and positioned substantially adjacent, with the thermistor.
40. The humidifier system of any of Claims 1 or 24-39, wherein the first electrically
conductive element and the second electrically conductive elernent are adjacent to each other.
41. The humidifier system of any of Clairns 1 or 24-39, wherein the first electrically
conductive element and the second electrically conductive element are not adjacent to each
other.
42. The humidifier system of any of Claims 1 or 24-41, wherein the first electncally
conductive element and the second electrically conductive elernent are within a bead of the
conduit.
43. The humidifier system of Cla1m 1, wherein the signal is mdicative of a resistance
of the first electrically conductive element or the second electrically conductive element.
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44. The humidifier system of any of Claims 1 or 43, wherem the first electncally
conductive element or the second electrically conductive element comprise at least two
portions that are electncally disconnected from one another.
45. The humidifier system of Cla1m 44, wherein the at least two portions protrude into
a lumen of the conduit.
46. The humidifier system of Claim 44, wherem the at least two portions are Hush with
an inner wall of the conduit.
47. The humidifier system of any of Claims 44-46, wherein the at least two portions
are arranged within the tube wall and are pneumatically coupled with the lumen of the conduit.
48. The humidifier system of any of Claims 44-47, wherein the at least two portions
are in series with one another.
49. The humidifier system of any of Claims 44-48, wherein the at least two portions
are in parallel with one another.
50. The humidifier system of Claim 1, wherein the controller determines a value
indicative of moisture in the conduit based at least in part on a magnitude and/or phase of the
signal
51. The humidifier system of any of Claims 1 or 50, fmiher comprising a signal
generator.
52. The humidifier system of any of Claims 1 or 50-51, wherein the signal has a
frequency bet\veen 30Hz and 300 GHz.
53. The humidifier system of any of Claims 1 or 50-51, wherein the signal has a
frequency between 1 MHz and 1 00 MHz.
54. The humidifier systern of any of Claims 1 or 50-51, wherem the signal has a
frequency of about 1 0 MHz.
55. The humidifier system of any of Clairns 1 or 50-54, wherein the first electrically
conductive element and/or the second electrically conductive element 1s a quarter of the
wavelength of the signal.
56. The humidifier system of any of Claims l or 50-54, wherein the wavelength of the
signal1s four times larger than the length of the first electrically conductive element and/or the
second electrically conductive element.
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57. The humidifier systern of any of Claims 51-56, wherein the signal generator injects
the signal mto the first electrically conductive element.
58. The humidifier system of any of Claims 1 or 50-57, wherein the first electncally
conductive element 1s configured to be a transmitter.
59. The humidifier system of any of Claims 1 or 50-58, wherein the second electncally
conductive element is configured to be a receiver to receive the signal transmitted by the first
electncally conductive element.
60. The humidifier system of any of Claims 1 or 50-59, wherein the magnitude and/or
phase of the signal is measured by a radio-frequency transducer.
61. The humidifier system of Claim 60, wherein the radio-frequency transducer can be
an Alvi receiver, RF sampling ADC, or RF rectifier.
62. The humidifier system of any of Claims 1 or 50-61, further comprising a filter to
filter the signal.
63. The humidifier system of Claim 62, wherein the filter comprises a high pass or
bandpass filter.
64. The humidifier system of any of Claims 62-63, \vherein the filter is configured to
filter out the mains frequency.
65. The humidifier system of any of Claims 62-64, w-herein the filter is configured to
filter out frequencies between 50-60Hz.
66. The humidifier system of any of Claims 58-65, wherein the transmitter comprises
a loop antenna.
67. The humidifier system of any of Claims 58-66, wherein the transmitter comprises
a monopole antenna.
68. The humidifier systern of any of Claims 59-67, wherein the receiver cmnprises a
loop antenna.
69. The humidifier systern of any of Claims 59-68, wherein the receiver cmnprises a
monopole antenna.
70. The humidifier system of any of Claims 1 or 50-69, wherein the first electncally
conductive element 1s electncally coupled to a first switch.
71. The humidifier system of any of Claims 1 or 50-70, wherein the second electncally
conductive element 1s electncally coupled to a second switch.
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72. The humidifier system of Claim 71, wherem the first switch 1s configured to
electrically disconnect one end of the first electncally conductive element.
73. The humidifier system of any ofClauns 71-72, the second switch 1s configured to
electrically disconnect one end of the second electrically conductive element.
74. The humidifier system of any of Clauns 71-73, wherein the first switch and/or the
second switch are located in any one of the following: a heater base, a sensor cartridge, the
conduit, an external component, or an mtermediate connector.
75. The humidifier system of any of Claims 1-74, wherein the controller is configured
to output an alarm if the value indicative of moisture falls below a first threshold value.
76. The humidifier system of any of Claims 1-75, wherein the controller is configured
to output an alarm if the value indicative of moisture exceeds a second threshold value.
77. The humidifier system of any of Claims 1-76, wherein the alarm indicates an
unacceptable level of moisture.
78. The humidifier system of any of Claims 1-77, wherein the controller is configured
to automatically reduce humidification of breathing or insufflation gases in response to the
value indicative of moisture and/or humidity in the conduit.
79. The humidifier system of any of Claims 1-78, wherein the reduction of humidity
delivered to the conduit is achieved by a reduction in heater plate power.
80. The humidifier system of any of Claims 1-79, wherein the conduit is a composite
conduit.
81. The humidifier system of any of Claims l-80, wherein the conduit comprises a
vapor and/or liquid permeable bead.
82. The humidifier systern of Claim 81, wherein the permeable bead allows evaporation
of water to ambient air while inhibiting passage of liquid water and breathing gases to ambient
mr.
83. The humidifier system of Claim 81, wherein the permeable bead is a one or rnore
of an activated perfluorinated polymer material having extrerne hydrophilic properties,
hydrophilic thermoplastic, breathable thermoplastic copolyester, woven treated fabnc
exhibiting breathable characteristics, or a hydrophilic polyester block copolymer.
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84. The humidifier system of any of Clauns 1-83, wherein the first electncally
conductive element and the second electrically conductive element are spirally wound about
at least a length of the conduit.
85. The humidifier system of any of Claims 1-84, wherein the first electrically
conductive element and the second electrically conductive element are sp1rally wound within,
through, or around the conduit.
86. The humidifier system of any of Cla1ms 1-85, wherein the first electncally
conductive element and the second electrically conductive element form part of the conduit
walls.
87. The humidifier system of any of Claims 1-86, wherein the first electrically
conductive element is a sensing wire.
88. The humidifier system of any of Claims 1-87, wherein the first electrically
conductive element is a heater wire.
89. The humidifier system of any of Claims l-88, wherein the second electrically
conductive element is a sensing wire.
90. The humidifier system of any of Claims l-89, wherein the second electrically
conductive element is a heater wire.